Hall Sending Unit Testing
- Test the special coil and the control unit as previously described. During the control unit test, check the wiring thoroughly and make certain that the terminals of the multiple connector at the distributor are clean and tight-fitting.
- On vehicles that have a digital idle stabilizer, disconnect both plugs from the digital idle stabilizer and connect the plugs together. If necessary, See Fig 2 -Fig 5 . Also disconnect the high tension cable from terminal 4 at the center tower of the distributor cap. Using an adaptor cable, solidly ground the disconnected high tension cable to some clean, unpainted metal part of the engine. This is to keep the engine from starting while you hand-turn the crankshaft in step 4.
- If necessary, turn off the ignition. Slide the rubber boot off the multiple connector for the control unit, and connect a voltmeter as indicated in Fig 1 & Fig 2 .
- Turn on the ignition. While you observe the voltmeter, use a wrench on the bolt in the center of the crankshaft pulley to hand-turn the pulley clockwise-thus turning the crankshaft in its normal direction or rotation. The voltage should fluctuate between at least 2 volts (Hall sending unit rotor aperture closed) and 0 volts (rotor aperture open).
- If the voltage did not fluctuate as specified in step 4, replace the Hall sending unit. With the ignition off, reconnect the digital idle stabilizer and the high tension cable when testing is complete. Then disconnect the voltmeter and reinstall the boot on the control unit's multiple connector plug.
NOTE:
If a new Hall sending unit, called an impulse coil in the parts lists, is unavailable, you should replace the breakerless distributor as a unit.